The group was formed on 11 May 1942, at Abingdon as No. 91 (Operational Training) Group RAF in RAF Bomber Command, it was previously No. 6 Group RAF. Within a matter of weeks it was called upon to provide over 200 aircraft and crews for Operation Millenium, the first 1,000 bomber raid, launched against Cologne on the night of 30/31 May 1942.[1]
On 14 April 1947, the Group moved to Morton Hall, Swinderby and was amalgamated with and renamed No. 21 Group RAF on 1 May 1947.[2]